<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<script>
    var arr = ["1","2","3"];
//    console.log(arr);
//    console.log(arr.length);

    console.log(arr[0]);
    console.log(arr[1]);
    console.log(arr[2]);

    arr[0] = "韩信";
    arr[1] = "萧何";
    arr[2] = "张良";

    console.log(arr[0]);
    console.log(arr[1]);
    console.log(arr[2]);
    console.log(arr[3]);
</script>
</body>
</html>